Start with measurable causes
Do not infer the source from one speed number. Compare the same device, destination and time under controlled conditions.
CONNECTION DIAGNOSIS
Packet Loss With Good Internet Speed?
A high throughput result does not rule out packet loss. Loss can be intermittent and may come from weak Wi-Fi, congestion, faulty equipment or an upstream route.
Compare, don’t guess
Repeat the loss test over Ethernet. Keep other variables stable, then change one condition at a time.
What can create this pattern
Wireless interference corrupts transmissions
Confirm this possibility with a repeatable comparison before changing equipment or service.
Congested queues discard packets
Confirm this possibility with a repeatable comparison before changing equipment or service.
A cable, modem or router is unstable
Confirm this possibility with a repeatable comparison before changing equipment or service.
An upstream route or endpoint has a problem
Confirm this possibility with a repeatable comparison before changing equipment or service.
Test it in this order
Repeat the loss test over Ethernet
Record the result, keep the test comparable and continue only after this step.
Compare devices and destinations
Record the result, keep the test comparable and continue only after this step.
Inspect cables and restart equipment
Record the result, keep the test comparable and continue only after this step.
Record when sustained loss occurs
Record the result, keep the test comparable and continue only after this step.
Use more than download speed
Read throughput together with ping, jitter and packet loss. A browser result describes this device, route and moment; it does not by itself prove an ISP fault.
Continue the diagnosis
packet loss jitter network qualityFrequently asked questions
Packet Loss With Good Internet Speed?
A high throughput result does not rule out packet loss. Loss can be intermittent and may come from weak Wi-Fi, congestion, faulty equipment or an upstream route.
What should I test first?
Repeat the loss test over Ethernet. Zero observed loss is ideal; sustained or bursty loss can harm calls and games.
Does one test prove the cause?
No. Repeat comparable tests over Ethernet and Wi-Fi, on more than one device and at different times.
MEASURE BEFORE YOU CHANGE
Start connection test →Find where the connection slows down
Save the result, repeat under comparable conditions and use the difference as evidence.